BookingWP - WooCommerce Appointments 4.22.1

* Improvement - Faster shop page rendering by caching global addon query.
* Improvement - Always add search for staff selection.
* Improvement - Filter 'woocommerce_product_is_in_stock' reinstated.
* Improvement - Updated php rrule to 2.2.2.
* Fix - PHP 8 issue with get_price_html() method.
* Fix - Fixed filter 'woocommerce_email_confirmed_recipients'.
* Fix - Fixed filter 'woocommerce_email_reminder_recipients'.
* Fix - Fixed filter 'woocommerce_email_follow_up_recipients'.
* Fix - Uploading files as add-on fields not working, when appointment added in admin.

* Improvement - Added 'woocommerce_appointments_get_addons' filter.
* Fix - PHP 8 issue with single '&' operator for comparison.

* Improvement - Added full Slovenian translation.
* Improvement - Compatibility with WooCommerce 4.9.
* Improvement - Integration with WooCommerce Multi Currency plugin.